FactoryGirl错误：未初始化的常量Post :: user

Question

我有点奇怪的命名空间错误处理FactoryGirl。该模型为Post ⤞ User。 代码是：

require 'factory_girl'
require 'active_record'

class User < ActiveRecord::Base ; end
class Post < ActiveRecord::Base
  has_one :moderator, class_name: :user
end

::FactoryGirl.define do
  factory :user do
    name 'Ghghghgh Ghghg'
  end
  factory :post do
    text 'Lorem ipsum etc'
    association :moderator, factory: :user, strategy: :create
  end
end

要求罚款，返回true。现在当我尝试生成一个实例时，我收到了这个错误：

FactoryGirl.create :post
#⇒ NameError: uninitialized constant Post::user

我错过了哪些明显的东西？